1、BRITISH STANDARD BS ISO 11925-3:1997 Incorporating Amendment No.1 Reaction to fire tests Ignitability of building products subjected to direct impingement of flame Part 3: Multi-source test ICS 13.220.50BSISO11925-3:1997 This British Standard, having been prepared under the directionof the Health an
2、d Environment Sector Board, waspublished under the authorityof the Standards Boardand comes into effect on 15February1998 BSI05-1999 ISBN 0 580 29225 8 National foreword This British Standard reproduces verbatim ISO11925-3:1997, including Technical Corrigendum1:1998, and implements it as the UK nati
3、onal standard. The UK participation in its preparation was entrusted by Technical Committee FSH/21, Reaction to fire tests, to Subcommittee FSH/21/2, Ignitability tests, which has the responsibility to: aid enquirers to understand the text; present to the responsible international/European committee
4、 any enquiries on the interpretation, or proposals for change, and keep the UK interests informed; monitor related international and European developments and promulgate them in the UK. A list of organizations represented on this subcommittee can be obtained on request to its secretary. The followin
5、g errors have been identified in this document: 1. Pageiv, Introduction, 4th paragraph, second line, replace “with” with “in”. 2. Page3, clause7.1 c) replace “growing duration” with “varying in size and intensity with time”. 3. Page16, Figure 5 move arrow1 to point to the next prong on the left. Del
6、ete item1 in the Key. Cross-references The British Standards which implement international or European publications referred to in this document may be found in the BSI Standards Catalogue under the section entitled “International Standards Correspondence Index”, or by using the “Find” facility of t
7、he BSI Standards Electronic Catalogue. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Su
8、mmary of pages This document comprises a front cover, an inside front cover, pages i and ii, theISO title page, pagesii to iv, pages1 to17 and a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on
9、the inside front cover. Amendments issued since publication Amd. No. Date Comments 10297 February 1999 Indicated by a sideline in the marginBSISO11925-3:1997 BSI 05-1999 i Contents Page National foreword Inside front cover Foreword iii Text of ISO11925-3 1ii blankBSISO11925-3:1997 ii BSI05-1999 Cont
10、ents Page Foreword iii Introduction 1 1 Scope 1 2 Normative reference 1 3 Definitions 2 4 Principle 2 5 Safety requirements 2 6 Ignition processes 2 7 Characteristics of ignition sources 3 8 Gas supply and regulation 3 9 Ignition sources 3 10 Specimens 4 11 Test apparatus 5 12 Testing room 6 13 Cond
11、itioning and testing atmospheres 6 14 Room ventilation 6 15 Flame application times 6 16 Test procedure 7 17 Observations during testing 8 18 Test report 8 Annex A (informative) Characteristics of ignition sources 16 Annex B (informative) Use by specifiers 16 Annex C (informative) Advice on testing
12、end-use products 16 Annex D (informative) Bibliography 17 Figure 1 Gas burner 9 Figure 2 Burner for ignition sources E and F 10 Figure 3 Test frame with draught shields 11 Figure 4 Burner carriage 12 Figure 5 Typical restraining comb for thermoplastic and flexible materials 13 Figure 6 Surface ignit
13、ion 14 Figure 7 Bottom edge ignition 15 Table 1 Specimen size and flame application times 6 Descriptors: Buildings, fire protection, building components, construction materials, tests, fire tests, flammability testing, determination, ignitability.BSISO11925-3:1997 BSI 05-1999 iii Foreword ISO (the I
14、nternational Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical committees. Each member body interested in a subject for which a technical committee
15、has been established has the right to be represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnica
16、l standardization. Draft International Standards adopted by the technical committees are circulated to the member bodies for approval before their acceptance as International Standards by the ISO Council. They are approved in accordance with ISO procedures requiring at least75% approval by the membe
17、r bodies voting. International Standard ISO11925-3 was prepared by Technical Committee ISO/TC92, Fire safety, Subcommittee SC1, Reaction to fire. ISO11925 consists of the following parts under the general title Reaction to fire tests Ignitability of building products subjected to direct impingement
18、of flame: Part 2: Single flame source test; Part 3: Multi-source test. Part1 is under preparation. Annex A to Annex D of this part of ISO11925 are for information only.iv blankBSISO11925-3:1997 BSI 05-1999 1 Introduction Fire is a complex phenomenon: its behaviour and effects depend upon a number of
19、 interrelated factors. The behaviour of materials and products depends upon the characteristics of the fire, the method of use of the materials and the environment in which they are exposed. The philosophy of “reaction to fire” tests is explained in ISO/TR3814. With the exception of rare cases of sp
20、ontaneous ignition, for any fire to start, whether smouldering or flaming, it is essential for some form of ignition source to be applied to, or in some way contact, a product in such a way that continuing combustion can take place. The ignition source can take three forms, something which imposes h
21、eat by conduction and/or radiation and/or convection. An example of ignition by conduction is by a hot wire coil or a hot metal bar; by radiation by an electric bar heater; and by convection by a convection heater or paint stripper. Usually, ignition sources of the radiative type include some degree
22、 of convection, and a flame includes a contribution from all three. Recourse to various material fire statistics shows that many fires start from a range of common sources which vary in intensity and severity. Frequent sources of fire have been found to be as follows: i) Cooking appliances ii) Space
23、 heating iii) Electrical wiring and installations iv) Other electrical appliances v) Cigarettes and smokers materials (i.e.matches, lighters) vi) Blow lamps, etc. vii) Rubbish burning viii) Candles A test such as is specified in this part of ISO11925 deals only with a simple representation of a part
24、icular aspect of a potential fire situation typified by a flame playing directly onto a material, composite or assembly. It cannot alone provide any direct guidance on behaviour or safety in fire. A test of this type may, however, be used for comparative purposes or to ensure the existence of a cert
25、ain quality of performance (in this case ignitability) considered to have a bearing on fire performance generally. It would be wrong to attach any other meaning to performance in this test. The term “ignitability” is defined in ISO/IEC Guide52 as the capability of a material of being ignited. It is
26、one of the first fire properties to be manifest and should almost always be taken into account in any assessment of fire hazard. It may not, however, be the main characteristic of the material which affects the subsequent development of fire in a building. This test does not rely upon the use of asb
27、estos-based materials. CAUTION So that suitable precautions may be taken to safeguard health, the attention of all concerned in fire tests is drawn to the possibility that toxic or harmful gases may be evolved during exposure of test specimens. The advice on safety given in clause5 should also be fo
28、llowed. 1 Scope This part of ISO11925 specifies a series of ignition sources which can be used for the determination of the ignitability of materials, composites and assemblies when subjected to direct impingement of flames of different size and intensity but without impressed irradiance. The source
29、s may be used in isolation or with the test method specified. This test method determines the ignitability of a material, composite or assembly and is not designed to assess any other fire parameter (e.g.flame spread). The possibility of the material composite or assembly causing secondary ignition
30、of other materials is also considered by the observation of burning droplets or debris which may be formed. NOTESecondary ignition of material in a growing fire situation can be addressed using ISO5657 which assesses the ignitability of building products by irradiance. 2 Normative reference The foll
31、owing standard contains provisions which, through reference in this text, constitute provisions of this part of ISO11925. At the time of publication, the edition indicated was valid. All standards are subject to revision, and parties to agreements based on this part of ISO11925 are encouraged to inv
32、estigate the possibility of applying the most recent editions of the standards indicated below. Members of IEC and ISO maintain registers of currently valid International Standards. ISO/IEC Guide52:1990, Glossary of fire terms and definitions. BSISO11925-3:1997 2 BSI 05-1999 3 Definitions For the pu
33、rposes of this part of ISO11925, the definitions given in ISO/IECGuide52 and the following apply. 3.1 sustained ignition after withdrawal of the ignition source, the presence of a flame on the surface of the specimen that persists for at least4s 3.2 transient ignition after withdrawal of the ignitio
34、n source, the appearance of flashes, or flames, which are not sustained for a continuous4s 3.3 progressive smouldering an exothermic oxidation not accompanied by flaming which is self-propagating (i.e.independent of the ignition source) and may be accompanied by incandescence 3.4 flaming debris matt
35、er flowing or separating from the specimen during the test procedure and falling below the initial lower edge of the specimen and continuing to flame as it falls 3.5 afterglow persistence of glowing of a specimen, under specified test conditions, after cessation of flaming or, if no flaming occurs,
36、after removal of the ignition source 3.6 flame application time the time (in seconds) for which the burner is in its final testing position 3.7 constant mass the state of a test specimen when two successive weighing operations, carried out at an interval of24h, do not differ by more than0,1% of the
37、mass of the specimen or0,1g, whichever is the greater 4 Principle Specimens are exposed to specified flames of different sizes and intensities and their ignition behaviour is observed. Annex C gives guidance on the application of this range of ignition sources to end-use products or specimens which
38、are not essentially flat. 5 Safety requirements There are hazards encountered when assessing the ignitability of any product using flame sources and it is essential that adequate precautions are taken. Particular attention should be paid to: the handling of flammable gases; the evolution of potentia
39、lly toxic gases; and the fact that extensive flaming of specimens may occur. The atmosphere of the testing room (seeclause12) may become hazardous and shall be cleared of smoke and toxic gases by an extractor fan or other means of ventilation. Adequate means of extinguishing the specimen should be p
40、rovided, bearing in mind that some specimens may produce severe flaming during the test. A hand and/or fixed water spray which can be directed over the burning area should be available with other means, such as fire extinguishers and fire blankets. NOTEIn some cases, smouldering may be difficult to
41、extinguish completely and immersion in water may be necessary. 6 Ignition processes 6.1 When building products are exposed to thermal energy, flammable vapours may be generated from their surface. Under suitable conditions (especially in high temperatures), a critical concentration of flammable vapo
42、ur may form and spontaneous ignition will result. If a flame is present as the sole energy source, or as a supplementary source, the ignition process will be assisted; this mechanism is sometimes known as pilot ignition. 6.2 A specimen of a building product is regarded as ignited when flames appear
43、on its surface. Ignition from the sources detailed in this standard may be transitory or sustained. 6.3 After ignition has occurred, some burning materials create additional fire hazards by forming flaming debris or drips. If this flaming debris falls onto combustible material, secondary ignition ma
44、y occur and the fire will spread more rapidly. 6.4 The localised application of a heat source to some materials may result in glowing combustion.BSISO11925-3:1997 BSI 05-1999 3 7 Characteristics of ignition sources 7.1 The main characteristics of ignition sources and their relation to the test speci
45、men may be defined by the following factors. a) The intensity of the ignition source. This is a measure of the heat flux on the specimen resulting from the combined conduction, convection and radiation effects caused by the ignition source. b) The area of impingement of the ignition source on the sp
46、ecimen. c) The duration of exposure of the specimen and whether it is continuous, intermittent or varying in size and intensity with time. d) The presentation of the ignition source to the specimen and whether or not it impinges. e) The orientation of the specimen in relation to the ignition source.
47、 f) The ventilation conditions in the vicinity of the ignition source and exposed surface of the specimen. 7.2 Flame ignition sources Two types have been selected. 7.2.1 Diffusion flame source To form a diffusion flame source, gas (e.g.propane) flows through stainless steel tubes without ingress of
48、air prior to the base of the flame. NOTEThese flames simulate natural flames well but they often fluctuate and are not convenient to direct if any angular presentation is required toward the specimen. 7.2.2 Premixed flame source To form a premixed flame source, use a gas burner (e.g.using propane) f
49、itted with air inlet ports or air intake manifold. NOTE 1Premixed flame sources are more directional than diffusion flame sources and are more suitable for some laboratory quality assurance tests. NOTE 2Premixed flame sources are generally hotter than diffusion flame sources. 8 Gas supply and regulation A supply of commercial propane connected to the ignition sources by: a) a cylindrical regulator with an outlet pressure of1bar absolute; b) an appropriate length of5mm internal diameter high pressure hose; c) two flowmeters with integral needle v
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